To answer your question the 7600's advantage over the 7400 is that the barrel is free floating on the 7600 and this aids in consistency. I had a 7600 a few years ago that was a real tack driver. It loved the old Remington load of a 120 gr. HP in the 280 Rem. This load has long been discontinued and the rifle was a decent shooter with 140 gr. Power Points but this load has also been discontinued. I traded the rifle for a bolt gun. I'm not a big fan of pumps.

I think alot of the inaccuracy reports of the 7400 are due to the poor triggers that come on this gun and most people that I know buy a couple of different boxes of ammo and go and shoot a group. If they can't cover 3 shots with a nickel they begin bad mouthing the gun. I had an uncle that had a 740 in 308 that would hold its own with about anything firing his handloads. He used the rifle for nearly 20 years until his death with no problems. He owned a number of bolt guns but for deer he usually picked up the old 308.

Take your rifle out and shoot it and see for yourself. You may be very surprised if you can learn to manage the trigger well.